MODELING ADSORPTION IN ALUMINUM-IRON BINARY OXIDE SUSPENSIONS

Experimental evidence indicates that particle-particle interactions (e.g., heterocoagulation, dissolution/adsorption/reprecipitation) signiticantly affect adsorbate distribution in Al-Fe binary oxide suspensions. To explore this behavior, two conceptual and mechanistic models of particle interactions in Al-Fe binary oxide suspensions are examined. One model assumes that soluble Al species compete with other adsorbates for Fe(OH)3 sites. The second model assumes that Fe(OH)3 surface sites are covered and replaced by active Al(OH)3 sites. The constant-capacitance model is used to test the models and estimate the effect of particle interactions on adsorbate distribution. The results suggest that the second model is appropriate for modeling trace element distribution among multicomponent solids. © 1990, American Chemical Society. All rights reserved.